Structure-Dependent Guest Recognition with Flexible Ferrocene-Based Aromatic Oligoamide β-Sheet Mimics.

Area of Science:

• Supramolecular Chemistry
• Organometallic Chemistry
• Molecular Recognition

Background:

• Aromatic oligoamides are versatile scaffolds for constructing complex molecular architectures.
• Ferrocene-containing molecules offer unique electronic and structural properties.
• Designing receptors for selective small molecule recognition remains a challenge.

Purpose of the Study:

• To synthesize and characterize novel aromatic oligoamides incorporating a ferrocene dicarboxylic acid unit.
• To investigate the conformational preferences and self-assembly behavior of these oligomers.
• To explore their potential for structure-dependent recognition of small polar molecules.

Main Methods:

• Synthesis of ferrocene-containing aromatic oligoamides.
• Solid-state and solution structural analyses (e.g., X-ray crystallography, NMR spectroscopy).
• Computational modeling (e.g., DFT calculations) to understand conformation and binding.
• Host-guest interaction studies to assess molecular recognition capabilities.

Main Results:

• Successful synthesis of a series of aromatic oligoamides featuring a flexible ferrocene dicarboxylic acid core.
• Demonstration of syn parallel stacked conformations leading to beta-sheet-like molecular clefts.
• Evidence of structure-dependent recognition of small polar molecules.
• NMR and theoretical studies confirmed an 'in cleft' binding mode and explained selectivity based on subtle structural variations.

Conclusions:

• Ferrocene-containing aromatic oligoamides can form well-defined molecular clefts through self-assembly.
• These clefts exhibit selective binding of small polar molecules, tunable by minor structural modifications.
• The study provides a foundation for designing sophisticated molecular receptors with organometallic components.